Radar transmission source detection device, radar transmission source detection drone, and radar transmission source detection program

Abstract

To calculate with high accuracy a horizontal position of a radar transmission source (such as a small vessel normally navigating and scanning radar waves).SOLUTION: In the present disclosure, one radar transmission source detection device R only receives radar waves without transmitting radar waves, but detects an altitude of an own device from a sea surface or a ground surface, and detects an arrival azimuth in a vertical direction and a horizontal direction of radar waves from a transmission source. Thus, the one radar transmission source detection device R can calculate a horizontal distance from the own device to the transmission source based on the altitude of the own device from the sea surface or the ground surface and the arrival azimuth in the vertical direction of the radar waves from the transmission source. Then, the one radar transmission source detection device R can calculate a horizontal azimuth from the own device to the transmission source based on the arrival azimuth in the horizontal direction of the radar waves from the transmission source.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a technique for calculating the horizontal position of a small vessel or the like. [Background technology]

[0002] In order to improve the safety of ship navigation, a technique using a simple AIS (Automatic Identification System) device and a technique using a ship radar device are known as conventional techniques for calculating the horizontal position of a small ship. However, in the technique using a simple AIS device, the installation rate of the simple AIS device is low among small ships (especially fishing boats and the like, which are not required to install an AIS device), and even if a simple AIS device is installed, the device power may be turned off so that the ship's position is not revealed, so only small ships equipped with a simple AIS device can be detected. In the technique using a ship radar device, small ships (e.g., the above-mentioned fishing boats and the like) are equipped with a ship radar device necessary for the ship's navigation at a high rate, and the ship radar device is always operated to scan radar waves, but since the cross-sectional area of ​​the radar reflection is small, it is difficult to detect small ships, especially when the waves are high. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-160031 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a technology that uses a direction finding system to calculate the horizontal position of a small vessel in order to improve the safety of vessel navigation. Figure 1 shows the problem to be solved by the conventional direction finding system. In Figure 1, a small vessel S is not equipped with a simple AIS device, and direction finding devices D1 and D2 are installed at a distance from each other in order to improve the accuracy of the intersection of the directions of arrival of the respective received signals (the horizontal position of the small vessel S), as will be described later.

[0005] In the left column of Figure 1, a small vessel S is not sailing normally and is transmitting a distress signal. Here, because the distress signal has a wide horizontal beam width, the direction finder devices D1 and D2 can receive distress signals having the same frequency almost simultaneously. Then, the direction finder devices D1 and D2 can determine that the distress signals they each receive are distress signals from the same source, and can detect the horizontal position of the small vessel S at the intersection of the arrival directions of each distress signal. However, the left column of Figure 1 cannot be applied to a small vessel S sailing normally. This is because the horizontal position cannot be detected because a distress signal is not being transmitted.

[0006] In the right column of Fig. 1, a small vessel S is sailing normally and scanning radar waves. Here, because the radar waves have a narrow horizontal beam width, the direction finders D1 and D2 cannot receive radar waves having the same frequency almost simultaneously. The direction finders D1 and D2 cannot determine that the radar waves they each receive are radar waves from the same source, and therefore cannot detect the horizontal position of the small vessel S at the intersection of the arrival directions of the radar waves.

[0007] Therefore, in order to solve the above problem, an object of the present disclosure is to calculate with high accuracy the horizontal position of a radar emission source (such as a small vessel normally navigating and scanning radar waves). [Means for solving the problem]

[0008] To solve the above problems, one radar source detection device only receives radar waves without transmitting radar waves, but detects its own altitude above sea level or above the ground, and detects the vertical and horizontal directions of arrival of the radar waves from the source.

[0009] Therefore, a radar source detection device can calculate the horizontal distance from the device itself to a radar source based on the altitude of the device from the sea level or ground and the vertical arrival direction of the radar wave from the radar source. Also, a radar source detection device can calculate the horizontal direction from the device itself to the radar source based on the horizontal arrival direction of the radar wave from the radar source.

[0010] Specifically, the present disclosure provides a vertical array antenna that receives radar waves from a source separate from the device itself by arranging multiple antenna elements in a vertical direction based on the coordinate system of the device itself; a horizontal array antenna that receives radar waves from a source separate from the device itself by arranging multiple antenna elements in a horizontal direction based on the coordinate system of the device itself; a device altitude detection unit that detects the altitude of the device from sea level or ground; and a vertical arrival antenna that detects the vertical arrival direction of the radar waves from the source received by the vertical array antenna based on the coordinate system of the device itself. a horizontal arrival direction detection unit that detects the horizontal arrival direction of the radar waves from the transmission source received by the horizontal array antenna based on a coordinate system of the device itself; a horizontal distance calculation unit that calculates the horizontal distance from the device itself to the transmission source based on the altitude of the device itself from sea level or ground and the vertical arrival direction of the radar waves from the transmission source; and a horizontal direction calculation unit that calculates the horizontal direction from the device itself to the transmission source based on the horizontal arrival direction of the radar waves from the transmission source.

[0011] According to this configuration, even without using multiple radar source detection devices, it is possible to use a single radar source detection device to calculate with high accuracy the horizontal position of the source relative to the position of the radar source itself, based on the horizontal distance and horizontal direction from the radar source detection device to the source.

[0012] The present disclosure also provides a radar source detection device that further includes a vertical front direction detection unit that detects in which direction and to what extent the front direction of the vertical array antenna is shifted based on the horizontal plane of the Earth's coordinate system, and is characterized in that the horizontal distance calculation unit calculates the horizontal distance from the device to the source based on the altitude of the device from sea level or ground, the vertical arrival direction of the radar waves from the source, and the front direction shift of the vertical array antenna based on the horizontal plane of the Earth's coordinate system.

[0013] With this configuration, even if a radar source detection device is swayed by wind or other factors in the sky, causing the front direction of the vertical array antenna to deviate from the horizontal plane of the Earth's coordinate system, the horizontal distance of the source based on the position of the device itself can be calculated with high accuracy.

[0014] The present disclosure also provides a radar source detection device further comprising a horizontal front direction detection unit that detects in which direction and to what extent the front direction of the horizontal array antenna is shifted based on a predetermined horizontal direction in the Earth's coordinate system, and the horizontal direction calculation unit calculates the horizontal direction from the device to the source based on the horizontal arrival direction of the radar waves from the source and the shift in the front direction of the horizontal array antenna based on the predetermined horizontal direction in the Earth's coordinate system.

[0015] With this configuration, by facing a single radar source detection device in any direction, even if the front direction of the horizontal array antenna deviates from a specified horizontal direction in the Earth's coordinate system, the horizontal direction of the source can be calculated with high accuracy based on the specified horizontal direction in the Earth's coordinate system.

[0016] The present disclosure also provides a radar source detection device further comprising an own device position detection unit that detects the position of the own device based on the Earth's coordinate system.

[0017] According to this configuration, using a single radar emission source detection device, the horizontal position of the emission source relative to the Earth's coordinate system can be calculated with high accuracy based on the horizontal position of the emission source relative to the position of the device itself and the position of the device relative to the Earth's coordinate system.

[0018] The present disclosure also provides a radar source detection device, characterized in that the source is a small vessel equipped with a radar device but not with an AIS (Automatic Identification System) device.

[0019] With this configuration, even without using multiple radar source detection devices, a single radar source detection device can be used to calculate with high accuracy the horizontal position of a small vessel that is navigating normally and scanning radar waves without being equipped with an AIS device, based on the position of the device itself.

[0020] The present disclosure also relates to a radar source detection drone equipped with the radar source detection device described above.

[0021] With this configuration, a drone having the effects described above can be provided.

[0022] The present disclosure also relates to a radar source detection program for causing a computer to execute each of the processing steps executed by the vertical arrival azimuth detection unit, the horizontal arrival azimuth detection unit, the horizontal distance calculation unit, and the horizontal azimuth calculation unit included in the radar source detection device described above.

[0023] According to this configuration, it is possible to provide a program having the above-described effects.

[0024] The above disclosed inventions can be combined to the greatest extent possible. Effect of the Invention

[0025] In this manner, the present disclosure can calculate the horizontal position of a radar source (such as a small vessel normally navigating and scanning radar waves) with high accuracy. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram showing a problem to be solved by a direction finding system according to the prior art. [Diagram 2] 1 is a diagram showing a configuration of a radar emission source detection device according to the present disclosure. [Diagram 3] FIG. 2 is a diagram showing the procedure of a radar emission source detection process according to the present disclosure. [Figure 4] FIG. 2 is a diagram illustrating the principle of the radar source detection process of the present disclosure. [Diagram 5] FIG. 1 illustrates the accuracy of the radar source detection process of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0028] (Overview of the radar source detection device of the present disclosure) The configuration of the radar emission source detection device of the present disclosure is shown in Fig. 2. The procedure of the radar emission source detection process of the present disclosure is shown in Fig. 3. The radar emission source detection device R includes an array antenna 1, an array receiving unit 2, an arrival direction detection unit 3, a horizontal position calculation unit 4, an apparatus information detection unit 5, an aircraft attitude control unit 6, and a radar emission source notification unit 7. The arrival direction detection unit 3, the horizontal position calculation unit 4, and the radar emission source notification unit 7 included in the radar emission source detection device R can be realized by installing the radar emission source detection program shown in Fig. 3 on a computer.

[0029] In the present disclosure, one radar source detection device R only receives radar waves without transmitting radar waves, but detects its own altitude above sea level or above the ground, and detects the vertical and horizontal arrival directions of the radar waves from the source.

[0030] Therefore, one radar emission source detection device R can calculate the horizontal distance from its own device to the emission source based on its own altitude from the sea level or ground and the vertical arrival direction of the radar wave from the emission source. And, one radar emission source detection device R can calculate the horizontal direction from its own device to the emission source based on the horizontal arrival direction of the radar wave from the emission source.

[0031] Therefore, without using multiple radar source detection devices R, it is possible to use a single radar source detection device R to calculate with high accuracy the horizontal position of the source based on the position of the device itself, based on the horizontal distance and horizontal direction from the device to the source.

[0032] (Principle of the Radar Source Detection Process of the Present Disclosure) The principle of the radar emission source detection process of the present disclosure is shown in Fig. 4. To improve the safety of ship navigation, a large ship L needs to obtain the horizontal position (0 m above sea level) of a small ship S with high accuracy. However, the small ship S is not equipped with a simple AIS device, but rather with a ship radar device. Therefore, a radar emission source detection drone D is equipped with a radar emission source detection device R, and while flying above the large ship L, it calculates the horizontal position of the small ship S with high accuracy.

[0033] The array antenna 1 is a patch array antenna or the like that includes a vertical array antenna 1V and a horizontal array antenna 1H. The vertical array antenna 1V has multiple antenna elements arranged vertically based on the coordinate system of the device itself (which may differ from the coordinate system of the Earth) and receives radar waves from the small vessel S. The horizontal array antenna 1H has multiple antenna elements arranged horizontally based on the coordinate system of the device itself and receives radar waves from the small vessel S.

[0034] The array receiver 2 is a multi-channel receiver or the like that includes a vertical array receiver 2V, a horizontal array receiver 2H, and a common local oscillator 2S. The vertical array receiver 2V down-converts the radar waves of the small vessel S received by the vertical array antenna 1V using the common local oscillator 2S. The horizontal array receiver 2H down-converts the radar waves of the small vessel S received by the horizontal array antenna 1H using the common local oscillator 2S.

[0035] The arrival direction detection unit 3 is a MUSIC (MUltiple SIgnal Classification) processing unit (capable of detecting multiple small vessels S) or a phase monopulse angle measurement unit (capable of detecting a single small vessel S) equipped with a vertical arrival direction detection unit 3V and a horizontal arrival direction detection unit 3H. The vertical arrival direction detection unit 3V detects the vertical arrival direction θ of the radar wave of the small vessel S received by the vertical array antenna 1V based on the coordinate system of the device itself (the front direction of the antenna) (step S1). The horizontal arrival direction detection unit 3H detects the horizontal arrival direction φ of the radar wave of the small vessel S received by the horizontal array antenna 1H based on the coordinate system of the device itself (the front direction of the antenna) (step S2).

[0036] Here, the marine radar device mounted on the small vessel S uses the X-band frequency band (9300-9500 MHz internationally, typically 9375, 9445±30 MHz). Therefore, the array receiver 2 and the arrival direction detector 3 receive radar waves and the like in a wide band, and then perform FFT (Fast Fourier Transform) processing, ignoring frequency bands other than the X-band, and only processing the X-band frequency band.

[0037] The host device information detection unit 5 includes a host device altitude detection unit 5A, a host device position detection unit 5P, a vertical front direction detection unit 5V, and a horizontal front direction detection unit 5H. The host device altitude detection unit 5A is a radar altimeter or the like, and detects the host device's altitude H from the sea level or the ground (sea level in FIG. 4). The host device position detection unit 5P is a GPS (Global Positioning System) device or the like, and detects the position (X, Y) of the host device based on the Earth's coordinate system.

[0038] The vertical front direction detection unit 5V is a gyro sensor or the like, and detects in which direction and to what extent (Δθ) the front direction of the vertical array antenna 1V is shifted with respect to the horizontal plane of the Earth's coordinate system. The horizontal front direction detection unit 5H is a compass or the like, and detects in which direction (e.g., clockwise angle) and to what extent (φ r ) to detect if it is misaligned.

[0039] The horizontal position calculation unit 4 includes a horizontal distance calculation unit 4R and a horizontal orientation calculation unit 4D. The horizontal distance calculation unit 4R obtains the altitude H of the device from sea level or ground level and the deviation Δθ of the vertical array antenna 1V in the front direction based on the horizontal plane of the Earth's coordinate system (steps S3 and S4). The horizontal orientation calculation unit 4D obtains the deviation φ of the horizontal array antenna 1H in the front direction based on a specific horizontal orientation of the Earth's coordinate system. r (Step S5). The aircraft attitude control unit 6 acquires this information and controls the attitude of the radar emission source detection drone D. The radar emission source notification unit 7 acquires the position (X, Y) of the device itself based on the Earth's coordinate system (Step S6).

[0040] The horizontal distance calculation unit 4R calculates the horizontal distance L = H / tan(θ-Δθ) from the device to the small vessel S based on the altitude H of the device from the sea surface, the vertical arrival direction θ of the radar wave from the small vessel S, and the frontal deviation Δθ of the vertical array antenna 1V based on the horizontal plane of the Earth's coordinate system (step S7). Here, if the radar source detection drone D is not shaking due to wind in the sky, the inclination of the drone is 0 and the frontal deviation Δθ of the vertical array antenna 1V based on the horizontal plane of the Earth's coordinate system is 0, so the horizontal distance calculation unit 4R only needs to calculate the horizontal distance L = H / tan θ from the device to the small vessel S.

[0041] The horizontal direction calculation unit 4D calculates the horizontal direction of arrival φ of the radar wave from the small vessel S and the front direction deviation φ of the horizontal array antenna 1H based on a predetermined horizontal direction of the Earth's coordinate system. r Based on this, the horizontal direction φ from the device to the small vessel S is calculated. d =φ+φ r Here, even if the radar source detection drone D is facing in any direction, the deviation φ in the front direction of the horizontal array antenna 1H based on a predetermined horizontal direction of the Earth's coordinate system is calculated. r If the horizontal direction calculation unit 4D does not consider the horizontal direction φ d It is sufficient to calculate =φ.

[0042] The radar source notification unit 7 is a WiFi (Wireless Fidelity) communication unit or the like, and receives a horizontal distance L from the device to the small vessel S and a horizontal direction φ from the device to the small vessel S. d and its own position (X, Y) are notified to the large ship L (step S9). The large ship L calculates the horizontal position of the small ship S based on this information.

[0043] Here, the radar source notification unit 7 determines the horizontal distance L from the device to the small vessel S and the horizontal direction φ dThe large ship L may then notify the large ship L of the above information (step S9). The large ship L may then calculate the horizontal position of the small ship S based on this information and the horizontal position of the radar emission source detection drone D calculated by the WiFi positioning device.

[0044] In this way, without using multiple radar source detection devices R, a single radar source detection device R can be used to calculate with high accuracy the horizontal position of a small vessel S that is navigating normally, is not equipped with an AIS device, and is scanning radar waves, based on the position of the device itself.

[0045] Furthermore, even if a radar source detection device R is swayed by wind or other factors in the sky, causing the forward direction of the vertical array antenna 1V to deviate from the horizontal plane of the Earth's coordinate system, the horizontal distance of the small vessel S based on the position of the device itself can be calculated with high accuracy.

[0046] On the other hand, by facing a single radar source detection device R in any direction, even if the forward direction of the horizontal array antenna 1H deviates from a specified horizontal orientation in the Earth's coordinate system, the horizontal orientation of the small vessel S based on the specified horizontal orientation in the Earth's coordinate system can be calculated with high accuracy.

[0047] Furthermore, using a single radar source detection device R, the horizontal position of the small vessel S based on the Earth's coordinate system can be calculated with high accuracy based on the horizontal position of the small vessel S based on the position of the device itself and the position of the device itself based on the Earth's coordinate system.

[0048] (Accuracy of the radar source detection process of the present disclosure) The accuracy of the radar source detection process of the present disclosure is shown in Fig. 5. In Fig. 5, the horizontal distance L = H / tan(θ-Δθ) from the radar source detection drone D to the small vessel S is plotted against the vertical arrival direction θ of the radar wave from the small vessel S, corrected for the forward deviation Δθ of the vertical array antenna 1V (tilt Δθ of the radar source detection drone D). A comparison is made between the cases where the altitude H of the radar source detection drone D from the sea surface is 150 m and 100 m.

[0049] Then, when the altitude H is 150 m, the horizontal distance L changes more rapidly with respect to the change in the vertical arrival azimuth θ-Δθ compared to when the altitude H is 100 m, so the calculation accuracy of the horizontal distance L is improved. When the altitude H is 150 m, the calculation upper limit value of the horizontal distance L reaches about 4000 m at the vertical arrival azimuth θ-Δθ = about 2 degrees. On the other hand, when the altitude H is 100 m, the calculation lower limit value of the horizontal distance L reaches several hundreds of meters at the vertical arrival azimuth θ-Δθ = about 20 degrees.

[0050] Here, the horizontal beam width of the radar wave from the small vessel S is narrowed, but the vertical beam width is widened. Therefore, even when the altitude H is 150 m, the received strength of the radar wave from the small vessel S does not decrease significantly compared to when the altitude H is 100 m.

[0051] (Application of the modified radar source detection device) In the present disclosure, the radar source detection device R is mounted on a radar source detection drone D and receives radar waves from a small vessel S. As a variant, the radar source detection device R may be mounted on a large vessel L and may receive radar waves from the small vessel S.

[0052] However, in the modified example, although the inclination Δθ of the large ship L is small, the height H of the mast of the large ship L is several tens of meters, so the calculation accuracy of the horizontal distance L decreases and the noise intensity for the radar waves of the small ship S may increase due to high waves or the blind spot of the ship itself.

[0053] On the other hand, in the present disclosure, although the inclination Δθ of the radar source detection drone D is large, the vertical arrival direction θ can be corrected, and the altitude H of the radar source detection drone D is approximately 100 m, improving the calculation accuracy of the horizontal distance L, and the noise intensity for the radar waves of the small vessel S does not increase due to high waves or the blind spot of the ship itself.

[0054] In the present disclosure, the radar emission source detection device R is mounted on a radar emission source detection drone D and receives radar waves from a small vessel S. As a modified example, the radar emission source detection device R may be mounted on a radar emission source detection drone D and receive radar waves or WiFi radio waves from a vehicle or the like on the ground, and may detect the altitude H of the drone relative to the vehicle or the like on the ground. [Industrial Applicability]

[0055] The radar source detection device, radar source detection drone, and radar source detection program disclosed herein can calculate the horizontal position of a radar source (such as a small vessel normally navigating and scanning radar waves, or, as a variant, including ground vehicles, etc.) with high accuracy. [Explanation of symbols]

[0056] S:Small ship L:Large ship D1, D2: Direction finding device R: Radar source detection device D: Radar source detection drone 1: Array antenna 1V: Vertical array antenna 1H: Horizontal array antenna 2: Array receiver 2V: Vertical array receiver 2H: Horizontal array receiver 2S: Common local oscillator 3: Direction of arrival detection section 3V: Vertical arrival direction detection section 3H: Horizontal direction of arrival detection section 4:Horizontal position calculation section 4V: Horizontal distance calculation section 4H:Horizontal direction calculation section 5: Self-device information detection unit 5A: Self-equipment altitude detection unit 5P: Device location detection unit 5V: Vertical front direction detection section 5H: Horizontal front direction detection section 6: Aircraft attitude control unit 7: Radar source notification unit

Claims

1. a vertical array antenna having a plurality of antenna elements arranged in a vertical direction based on a coordinate system of the own device and configured to receive radar waves from a transmission source separate from the own device; a horizontal array antenna having a plurality of antenna elements arranged in a horizontal direction based on a coordinate system of the own device and configured to receive radar waves from the radar source separate from the own device; an altitude detection unit for detecting an altitude of the device from sea level or ground; a vertical arrival direction detection unit that detects a vertical arrival direction of the radar wave from the transmission source received by the vertical array antenna, based on a coordinate system of the own device; a horizontal arrival direction detection unit that detects a horizontal arrival direction of the radar wave from the transmission source received by the horizontal array antenna, based on a coordinate system of the own device; a horizontal distance calculation unit that calculates a horizontal distance from the device to the source based on an altitude of the device from sea level or ground level and a vertical arrival direction of the radar wave from the source; a horizontal direction calculation unit that calculates a horizontal direction from the device to the transmission source based on a horizontal direction of arrival of the radar wave from the transmission source; A radar source detection device comprising:

2. a vertical front direction detection unit that detects in which direction and to what extent the front direction of the vertical array antenna is deviated based on a horizontal plane of the earth's coordinate system; The horizontal distance calculation unit calculates the horizontal distance from the device to the source based on the altitude of the device from sea level or ground, the vertical arrival direction of the radar wave from the source, and the deviation of the front direction of the vertical array antenna based on the horizontal plane of the Earth's coordinate system.

2. A radar source detection device as claimed in claim 1.

3. a horizontal front direction detection unit that detects in which direction and to what extent the front direction of the horizontal array antenna is deviated based on a predetermined horizontal direction of the earth's coordinate system; The horizontal direction calculation unit calculates a horizontal direction from the device to the source based on a horizontal direction of arrival of the radar wave from the source and a deviation of a front direction of the horizontal array antenna based on the predetermined horizontal direction of the Earth's coordinate system.

3. A radar source detection device according to claim 1 or 2.

4. a device position detection unit that detects a position of the device based on a coordinate system of the earth; 2. The radar source detection apparatus of claim 1 further comprising:

5. The source is a small vessel equipped with a radar device but not an AIS (Automatic Identification System) device.

2. A radar source detection device as claimed in claim 1.

6. A radar source detection drone comprising the radar source detection device according to claim 1.

7. 2. A radar source detection program for causing a computer to execute each processing step executed by the vertical arrival azimuth detection unit, the horizontal arrival azimuth detection unit, the horizontal distance calculation unit, and the horizontal azimuth calculation unit of the radar source detection device according to claim 1.

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